There are a wide variety of uses for non-linear plastic products. One field where curved plastic products find use is in the building industry. A variety of plastics are finding increasing use in buildings particularly due to their weatherability characteristics such as water-repellency and color-fastness, and their relative light weight and strength. There is increasing demand for curved plastic building members not only due to their ability to bear and distribute stress, but because they allow a greater degree of architectural freedom in the design of buildings. Curved plastic members allow the builder to create modern designs as well as to recreate the curvature of wood found in classic architectural styles.
One such use for curved plastics is in the field of window and door frames. Arched window or door frames in the past have been created by reshaping a linear extruded plastic piece through the use of elaborate table jig systems. The linear plastic extrudate is softened by heating and laid onto a table jig having a large number of stress clamps. These clamps must be painstakingly aligned to bring the plastic piece into the desired shape. Such table jig systems are expensive and require time-consuming effort by skilled operators to produce a finished product. Each curved plastic piece must be individually produced by the application of heat energy to a linear plastic piece which usually has been extruded through the use of energy during the extrusion process. Accordingly, the present method for producing consistently and accurately shaped curved plastic pieces is both energy and labor intensive, and requires the use of expensive, specialized equipment by skilled craftsman. One of the obstacles to producing many such curved plastic pieces is that, in many instances, the curved plastic pieces must conform to a builder's dimensional specifications and tolerances in order to be compatible with the other building materials with which they will be used. For instance, curved plastic pieces for use in window and door frame pieces generally must have consistent curvature and cross-section or "profile " in order to fit together both with the building itself and the other window and door components.
Accordingly, it is an object of the present invention to be able to produce curved plastic pieces in a relatively fast, continuous process.
It is also an object of the present invention that such curved plastic pieces be so produced while maintaining appropriately accurate curvature and cross-section in the piece.
Yet another object of the present invention to be able to produce such curved plastic pieces in a process which is less labor intensive and requires no specialized jig system or the efforts of skilled operators.
In light of the present disclosure and the practice of the present invention, other advantages and the solutions the other problems my become apparent to one of ordinary skill in the relevant art.